Pazopanib is an angiogenesis inhibitor targeting vascular endothelial growth factor receptors (VEGFR)-1, -2, and -3, platelet-derived growth factor receptors (PDGFR)-α/-β, and c-Kit. The hydrochloride salt of pazopanib (5-[[4-[(2,3-dimethyl-2H-indazol-6-yl)methylamino]-2-pyrimidinyl]amino]-2-methylbenzenesulfonamide) is marketed by GlaxoSmithKline as Votrient®, which is approved in the United States and other countries for the treatment of renal cell carcinoma (RCC).
Votrient® is currently prescribed to adults in the form of 200 mg tablets for oral administration, with each 200 mg tablet containing an amount of pazopanib hydrochloride equivalent to 200 mg of pazopanib free base.
Though the current tablets are acceptable of use in adults, the tablets are not preferred for use in potential future use for administering pazopanib to children. In pediatric populations, it is often desired that drug be available as a powder for reconstitution to an oral suspension. Manufacture of such a powder requires dry blending of various excipients with the active substance to provide good flow properties and content uniformity of the powder blend.
Several additional challenges exist concerning the use of pazopanib in a pediatric formulation. For instance, the nature of the drug substance favors conversion from the hydrochloride salt to the free base and hydrate forms in an aqueous environment such that standard formulations fail to provide adequate suspension stability at long term storage conditions of 25° C./65% RH or room temperature. Further, the drug has been found to have a bitter taste and, therefore, taste masking is critical.
It is desired to invent a pediatric formulation of pazopanib hydrochloride suitable for administration to a pediatric population.